Jack,
I've looked at your Flickr setups for the last two shoots, and have to agree that the on-the-floor speedlight isn't doing too much good. I think your setups are lacking a strong, higher-than-the-nose main light source that has some direction to it. Shooting the flash through the overhead-mounted bed sheet is producing a soft,diffused light that has very little direction to it, and as a result the photos are lacking crispness....the light is just soft and dull.
I saw the DIY foil turkey pan light you've made. Look forward to seeing that deployed as a simple main light. One good thing about your new setup--you've managed to get a clean white background,and you seem to have decent rapport with the subjects. Hope the SAT thing went okay!